The three-dimensional (also: 3D) imaging technologies, time-of-flight cameras (3D-LMI), structured-light 3D imaging and stereovision systems all have specific weaknesses and drawbacks as well as advantages depending on the specific conditions encountered in the scene to be analyzed. Examples are background illumination conditions, presence or absence of particular surface texture pattern in objects, size of the objects, or the speed of objects in the scene. By combining three-dimensional measurement techniques, which are partially complementary in their performance, a higher precision and a higher reliability level can be achieved. In this respect, also a combination with additional high-resolution 2D imaging can be useful. The different 3D techniques require each a highly specialized illumination system. If each illumination system were to be implemented separately, this would represent a large cost contribution in hybrid systems, as the cost for high power lasers is high. In addition, it is difficult to integrate elegantly several separate illumination systems for the different types of imaging of hybrid systems into a compact instrument.
A list of reference documents can be found at the end of the detailed description.